Medical marijuana laws enjoy broad public support in the United States. Fifteen states and the District of Columbia have medical marijuana laws on the books and several states are contemplating similar legislation. Recent polls indicate that over 70 percent of Americans favor state laws allowing marijuana use for prescribed medical purposes (The Pew Research Center 2010). Despite their popularity, relatively few studies have considered how medical marijuana policies affect recreational marijuana use or individual and public health outcomes. The few published quantitative studies on the topic find disparate results, with some finding evidence consistent with higher recreational demand (Pacula et al. 2010) and others finding no relationship to recreational use (Gorman and Huber, 2007) or perceived harm of marijuana (Khatapoush and Hallfors, 2004). The goal of our work is to provide the most complete accounting to date of the nuanced features of medical marijuana laws and their implications for health. To do this we will examine the implementation of medical marijuana laws at the state, county and city level and assess whether provisions related to the supply of medical marijuana for patients influence access and use among recreational users. We will further consider whether and how these laws relate to harms caused by marijuana misuse/abuse including accidents, asthma, acute psychoses, alcohol dependence, schizophrenia, drugged driving, and crime. We will analyze these individual and public health outcomes at all three geographic levels allowing us to test the external validity of findings from any single data source or analysis as well as better understand whether the specifics of how laws get implemented is more important than the broad law itself. Our work should contribute to improved policymaking relating to medical marijuana by identifying the dimensions of state and local policy that are most clearly linked to individual and public health outcomes. By making our systematic coding of medical marijuana policies at the state, county and local levels available to other researchers, we will also lay the groundwork for future work in this area.